The present disclosure relates to a cleaning device for use to clean an image carrier capable of carrying a toner image, an image carrier unit including the cleaning device, and an image forming apparatus including the cleaning device.
A known image forming apparatus for use to form an image on a sheet (recording medium) employs a technique in which the sheet passes up from below through a transfer nip formed between a photosensitive drum and a transfer roller. A toner image is formed on the photosensitive drum and the formed toner image is then transferred to the sheet at the transfer nip. The image forming apparatus further includes a fixing section. The sheet having the toner image transferred thereto undergoes a fixing process in the fixing section and is then output.
In this technique, in order to clean up residual toner on the photosensitive drum after the transfer of the toner image at the transfer nip, a cleaning device is disposed facing the photosensitive drum. In the case where, as above, the sheet passes up from below through the transfer nip, the cleaning device located downstream of the transfer nip in the direction of rotation of the photosensitive drum is mostly disposed above the photosensitive drum.
When like this the cleaning device is disposed above the photosensitive drum, residual toner removed from the photosensitive drum may fall from around the cleaning device. Therefore, a toner sealing member is provided around the cleaning device and held in contact with the photosensitive drum in order to prevent residual toner from falling. However, if a large amount of toner piles up on top of the toner sealing member, the toner presses the toner sealing member against the photosensitive drum. Thus, the contact pressure of the toner sealing member against the photosensitive drum is increased. If in this state paper powder of a sheet adheres to the cylindrical surface of the photosensitive drum at the transfer nip and moves to the distal end of the toner sealing member with the rotation of the photosensitive drum, the paper powder grows with time into a mass between the distal end of the toner sealing member and the cylindrical surface of the photosensitive drum. As a result, the mass of paper powder may lift up the distal end of the toner sealing member to cause troubles, such as toner leakage.